pmbus: tps544: adapt for updated pmbus interfaces

Because of commit 43f33b6e ("hwmon: (pmbus) Add 'phase' parameter
where needed for multi-phase support"), the function "pmbus_read_word_data"
needs one more argument "phase". Since tps544 doesn't support
multi-phase, this "phase" argument will be ignored. Let's pass "0xff"
to pmbus_read_word_data just to avoid compile error.

Because of commit dd431939 ("hwmon (pmbus) use simple i2c probe
function"), remove "id" argument from tps544_probe since pmbus_do_probe
doesn't need it anymore.

Because of commit 3bce071a ("hwmon: (pmbus) shrink code and remove
pmbus_do_remove()"), remove the obsolete function "pmbus_do_remove".

Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>